﻿using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace School
{
    public class School
    {
        private static HashSet<Student> set = new HashSet<Student>();

        public static bool Add(Student student)
        {
            if (set.Contains(student))
            {
                return false;
            }
            else
            {
                set.Add(student);
                return true;
            }
        }
    }
}
